HUDSON FORMULA
This is the Javascript version of the Hudson Formula
for preliminary design of breakwaters.Disclaimer: do not use
these results for design purposes. This formula applies
only to preliminary design. Your breakwater should be
tested in a physical model before being built !

"Following work by
Irribarren (1938, 1950), comprehensive investigations
were made by Hudson (1953, 1959, 1961) at the U.S. Army
Corps of Engineer Waterways Experiment Station (WES) and
a formula was developed to determine the stability of
armor units on rubble structures. The stability formula,
based on the results of extensive small-scale model
testing and some preliminary verification by large-scale
model testing, is known by Hudson Formula". Shore
Protection Manual, 1984.

W - weight of an
individual armor unit in the primary cover layer.
When the cover layer is two quarry stones in
tickness, the stones comprising the primary cover
layer can range from about 0.75 W to 1.25 W with
about 50% of the individual stones weighting more
than W. The maximum weight of individual stones
depends on the size or shape of the unit. The unit
should not be of such a size as to extend an
appreciable distance above the average level of the
slope.